Trends in the weight status of adults in Ireland between 1990 and 2024

Purpose: This study aimed to establish trends in overweight and obesity prevalence among adults living in Ireland (18-64 years) and older adults (> 65 years) over three decades, from 1990 to 2024. Methods: Anthropometric data pertaining to n4357 adults were collated from four nationally representative, cross-sectional nutrition surveys published in Ireland between 1990 and 2024. These anthropometric data were measured by researchers in three of the four datasets, and self-measured in the fourth. X2 tests and one-way analysis of variance (ANOVA) were used to test for significant differences. Binary logistic regression explored the association between sociodemographic variables and the presence of overweight and obesity. Results: Significant increases in mean height and weight were observed between 1990 and 2011, across both age groups (18-64 years and > 65 years) and sexes (p ≤ 0.001). A decrease was observed in mean weight and BMI among the more recent 2024 cross-sectional sample (p < 0.001). A similar pattern was noted in the prevalence of those living with obesity with 11.5% presenting with obesity in 1990, increasing to 23.7% 2011, and declining to 17.3% in 2024 among the adults aged 18-64 years. The proportion of older adults living with obesity between 1990 and 2024 followed a similar trajectory. Social class was associated with the presence of overweight and obesity, with the greatest association noted among the 2011 cross-sectional sample (p = 0.003). Conclusion: Weight status increased during the period 1990-2024, with the more recent data indicating a possible plateau emerging, methodological differences between the studies included hinder certainty. Consistent associations between social class and the presence of overweight and obesity are noted. Continuous monitoring of weight status is required to confirm the trends noted in the present study and to guide population wide public health measures related to weight status.